Annual or perennial herbs covered with sticky glandular hairs. Leaves opposite, margins entire or toothed occasionally lobed, stipule absent. Inflorescence axillary or terminal racemes. Flowers irregular, bisexual 5-merous. Sepals 2, free or fused and split on one side. Petals tubular expanding towards the apex, 5-lobed and often 2-lipped. Stamens epipetalous fertile and staminodes present. Ovary superior, style slender, with 2 stigmatic flaps. Fruit a woody capsule with a fleshy outer layer, dehiscing longitudinally. Seeds many, compressed, black. 5 gen., cosmop.